Investment Securities - Summary of Amortized Cost and Fair Value by Contractual Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Amortized Cost, 1 year or less	$ 381
Amortized Cost, Due after one year through five years	9,030
Amortized Cost, Due after five years through ten years	13,432
Amortized Cost, Due after ten years	25,464
Amortized Cost, Mortgage-backed securities and Collateralized Mortgage Obligations	40,987
Amortized Cost	89,294	$ 86,920
Fair Value, 1 year or less	377
Fair Value, Due after one year through five years	8,639
Fair Value, Due after five years through ten years	12,134
Fair Value, Due after ten years	21,190
Fair Value, Mortgage-backed securities and Collateralized Mortgage Obligations	36,439
Fair Value	78,779	78,813
Held to Maturity Securities Amortized Cost, 1 year or less	0
Held to Maturity Securities Amortized Cost, Due after one year through five years	6,000
Held to Maturity Securities Amortized Cost, Due after five years through ten years	9,000
Held to Maturity Securities Amortized Cost, Due after ten year	0
Mortgage-backed securities and Collateralized mortgage obligations	22,778
Held-to-Maturity, Amortized Cost	37,778	31,822
Held to Maturity Securities Fair Value, 1 year or less	0
Held to Maturity Securities Fair Value, Due after one year through five years	5,673
Held to Maturity Securities Fair Value, Due after five years through ten years	7,364
Held to Maturity Securities Fair Value, Due after ten years	0
Mortgage-backed securities and Collateralized mortgage obligations	21,551
Held-to-maturity, Fair Value	$ 34,588	$ 30,080